Problem: Simplify the following expression: $3\sqrt{12}$.
Explanation: First, try to factor a perfect square out of the radical. $= 3\sqrt{12}$ $= 3\sqrt{4 \cdot 3}$ Separate the radical and simplify. $= 3\sqrt{4} \cdot \sqrt{3}$ $= 3 \cdot 2 \cdot \sqrt{3}$ $= 6\sqrt{3}$